A wide variety of work implements are used to perform various tasks, and it is often desirable to facilitate the use of different implements with different machines. Despite the desire for flexibility, manufacturers often produce implements such as buckets, blades, scoops, forks, etc. with coupling hardware that is specific to one machine. In other words, a machine such as an excavating machine may be designed to work with a relatively small number, or certain class of implements, and may have limited ability to pick up and utilize a different class or type of implement without substantial modification to either the machine or the implements and/or coupling hardware itself. Implement-linkage compatibility issues arise frequently where an operator or owner having one machine wishes to use the machine with implements not specifically designed for that machine. Such issues also may arise where a manufacturer offers a new line of machines, a new line of coupling assemblies, or even a new line of implements, and owners or operators wish to continue to use the old machines, implements, etc. with the new line of products.
In one specific example, certain buckets for excavating machines and loaders may have a coupling width compatible with one machine, but incompatible with machines having a different coupling width on the corresponding parts of the linkage or coupling assembly. It is common in certain construction machines to utilize an apparatus called a pin grabber which is configured to couple a hook mounted on a linkage with a pin that is mounted on a bucket. In an attempt to adapt a wider width pin for coupling with a relatively lesser width hook, engineers have utilized free-floating spacers or shims positioned on the pin. The environment within which coupling between a machine and a bucket takes place can subject the coupling hardware to relatively high forces and wear, tending to damage certain of the components over multiple coupling/decoupling cycles. In particular, as an operator moves a linkage to a position at which the associated pin grabber can engage with a pin, he or she may inadvertently strike certain areas of the coupling hardware with the hook, as the hook settles to a desired position about the pin.
The relatively severe stresses involved in such procedures have rendered earlier attempts to use loose spacers or shims to adapt the pin coupling width relatively ineffective. Not only do free floating spacers often require an operator to dismount from the machine and position the spacers at appropriate locations, the engagement of the hook about the pin can break or otherwise damage the spacers. It is thus desirable to provide for an improved means of adapting a coupling width of pins on certain implements for easy attachment with a machine having a different coupling width, without subjecting the coupling hardware to undue stress, strain and premature failure.
As alluded to above, free-floating spacers and shims have clear drawbacks. A need for securing machine parts against axial displacement along a shaft has been recognized for decades. In many traditional designs, parts can be prevented from movement along a shaft via articles known as retaining rings, split-rings and the like. One example of such a retaining ring is known from U.S. Pat. No. 2,491,310 to Heimann. Heimann proposes a retaining ring which is open-ended and adapted to be positioned in a groove provided in a shaft or the like. The purpose of Heimanns' retaining ring is stated to be providing an artificial shaft or pin shoulder to prevent the movement of machine parts in an undesired manner. Heimanns' retaining ring appears capable of exerting pressure against the bottom of its seating groove in the axial shaft or pin, to achieve its stated purposes. This represents one strategy applicable in certain machine environments. Its intended use with a groove on the shaft is undesirable, however, in that the shaft must be modified to form the groove, potentially reducing the integrity of the shaft, and also requiring machining steps to adapt a particular shaft for use with Heimanns' retaining ring, drawbacks which are unacceptable in many machine applications.